Original URL: http://www.psxextreme.com/psp-cheat-print/137.html
Sega Genesis Collection

Altered Beast

Continue:
Hold Square, push start repeatedly

Level Select:
Enable Options, choose a level, and press Start while holding Square

Secret Options:
On the title screen, hold X and push Start

Choose Music
On the title screen, hold Square, X, Circle, Down, Left, and Start

Sound Test
On the title screen, hold Square, Circle, Up/Right, and Start

Sonic the Hedgehog

Level Select
At the title screen, press Up, Down, Left, Right, and press start while holding X.